ᐅ Parapet construction on flat roofs

We plan to build our house using 24 cm (9.5 inches) Poroton bricks. An external thermal insulation composite system (ETICS) will be applied on top. The flat roof will be a reinforced concrete slab.

Now, the question is about the construction of the parapet. The current offer for one row of Poroton bricks topped with a U-shaped form and ring beam is quite expensive.

My idea is to lay or glue two rows of sand-lime bricks on the last floor slab to reach the required parapet height of 50 cm (20 inches), and that should be sufficient. On top of that would come insulation, an OSB board, and then the aluminum flashing. The roof covering will be a bitumen membrane.

My question is: Is this solid masonry wall enough as a parapet, or do I need to cast a concrete ring beam as a finishing element? After all, only the wind load acts as a horizontal force on this 50 cm (20 inches) high wall panel.

I would appreciate some input.
Best regards, André

Yes, the parapet technically slopes downwards in strong wind.
A cost-effective parapet is made with wood and OSB.
Or without a parapet, which can also look nice if done well.
Concrete blocks with a steel bar placed between the layers are another affordable DIY solution.

I had already considered using concrete blocks for the walls. I don’t want wood for the parapet, since that would mean almost nothing on the house would be made of wood. I want everything to be solid. My only real question was whether the horizontal load from the wind would really be strong enough to topple two rows of bricks. I can’t imagine that happening with a wall thickness of 24 cm (9.5 inches). Because of the self-weight, I also want to use sand-lime bricks deliberately.

Practically, nothing will probably happen, but mathematically it is not possible.

Lumpi_LE schrieb:

Or without a parapet, it also looks sleek if done well.

Flat roof without a parapet? Is that possible and, if so, how?

I would appreciate serious clarification, as I find this really interesting.

Consider the opportunity costs. How much more expensive will completing the Poroton bricks be with a different attic solution?